Comparative study of gas accumulations in the Permian Changxing reefs and Triassic Feixianguan oolitic reservoirs between Longgang and Luojiazhai-Puguang in the Sichuan Basin  

作　　者：ZHAO WenZhi XU ChunChun WANG TongShan WANG HongJun WANG ZeCheng BIAN CongSheng LI Xia 

机构地区：[1]PetroChina Exploration ＆ Production Company, Beijing 100007, China [2]PetroChina Southwest Oil ＆ Gas Field Company, Chengdu 610051, China [3]PetroChina Research Institute of Petroleum Exploration ＆ Development, Beijing 100083, China

出　　处：《Chinese Science Bulletin》2011年第31期3310-3320,共11页

基　　金：supported by the National Basic Research Program of China (2007CB209500);the National Special Program of Science and Technology in China (2008ZX05004)

摘　　要：Reef and oolitic gas reservoirs in the Permian Changxing and Triassic Feixianguan formations have been discovered in both the Luojiazhai-Puguang and Longgang areas of the Sichuan Basin, but the accumulation scale, abundance and distribution patterns differ greatly. In fact, the two areas have more differences than they have similarities. Similarities include: (1) the lithology, properties and types of porosity of the reef and oolitic reservoirs are primarily consistent in the two areas; (2) well-developed regional caprocks that seal the fluid system; and (3) accumulation process histories, with liquid hydrocarbon charging at an early stage, cracking into gas at a high to over-mature stage, adjustment of gas reservoirs at an uplifting stage, and final reservoir generation at a late stage. Differences include: (1) gas accumulations in the Luojiazhai-Puguang area that are dominated by oil-type cracked gas, with multiple and sufficient gas sources, contrasting with gas accumulations in the Longgang area that are dominated by coal-sourced gas with insufficient gas sources; (2) heterogeneity and horizontal diversity of reservoirs in the Longgang area that are stronger than in the Luojiazhai-Puguang area; and (3) the development of deep and large faults in the Luojiazhai-Puguang area that link source, reservoir and migration pathways, contrasting with poorly developed faults in Longgang area, where laterally variable fractures are the major migration pathway. Because of these differences, abundant large-scale structurally-controlled gas accumulations are developed in the Luojiazhai-Puguang area, whereas lithology plays a more important role in gas accumulation in the Longgang area where accumulations are smaller-scale and have lower gas-bearing abundance. We suggest that future exploration for reef and oolitic gas accumulations should be strengthened in NE Sichuan and NW Sichuan Jiulongshan. In particular, the transitional zone between Longgang and Kaijiang-Liangping Bay has the best potential for new discoveries.Reef and oolitic gas reservoirs in the Permian Changxing and Triassic Feixianguan formations have been discovered in both the Luojiazhai-Puguang and Longgang areas of the Sichuan Basin, but the accumulation scale, abundance and distribution patterns differ greatly. In fact, the two areas have more differences than they have similarities. Similarities include： （1） the lithology, properties and types of porosity of the reef and oolitic reservoirs are primarily consistent in the two areas; （2） well-developed regional caprocks that seal the fluid system; and （3） accumulation process histories, with liquid hydrocarbon charging at an early stage, cracking into gas at a high to over-mature stage, adjustment of gas reservoirs at an uplifting stage, and final reservoir generation at a late stage. Differences include： （1） gas accumulations in the Luojiazhai-Puguang area that are dominated by oil-type cracked gas, with multiple and sufficient gas sources, contrasting with gas accumulations in the Longgang area that are dominated by coal-sourced gas with insufficient gas sources; （2） heterogeneity and horizontal diversity of reservoirs in the Longgang area that are stronger than in the Luojiazhai-Puguang area; and （3） the development of deep and large faults in the Luojiazhai-Puguang area that link source, reservoir and migration pathways, contrasting with poorly developed faults in Longgang area, where laterally variable fractures are the major migration pathway. Because of these differences, abundant large-scale structurally-controlled gas accumulations are developed in the Luojiazhai-Puguang area, whereas lithology plays a more important role in gas accumulation in the Longgang area where accumulations are smaller-scale and have lower gas-bearing abundance. We suggest that future exploration for reef and oolitic gas accumulations should be strengthened in NE Sichuan and NW Sichuan Jiulongshan. In particular, the transitional zone between Longgang and Kaijiang-Liangping Bay has the best potentia

关 键 词：四川盆地东北部 飞仙关组鲕滩 鲕滩气藏 三叠系 珊瑚礁 水库 地龙 二叠世 

分 类 号：P618.13[天文地球—矿床学]